/**
 * Copyright (c) 2012-2016, www.tinygroup.org (luo_guo@icloud.com).
 *
 *  Licensed under the GPL, Version 3.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *       http://www.gnu.org/licenses/gpl.html
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.tinygroup.jspengine.compiler;

import org.tinygroup.jspengine.Constants;
import org.tinygroup.jspengine.JasperException;
import org.tinygroup.jspengine.JspCompilationContext;
import org.tinygroup.jspengine.runtime.JspSourceDependent;
import org.tinygroup.jspengine.servlet.JspServletWrapper;

import javax.servlet.jsp.tagext.*;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.URLClassLoader;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Vector;

/**
 * 1. Processes and extracts the directive info in a tag file.
 * 2. Compiles and loads tag files used in a JSP file.
 *
 * @author Kin-man Chung
 */

class TagFileProcessor {

    private Vector tempVector;

    /**
     * Parses the tag file, and collects information on the directives included
     * in it.  The method is used to obtain the info on the tag file, when the
     * handler that it represents is referenced.  The tag file is not compiled
     * here.
     *
     * @param pc         the current ParserController used in this compilation
     * @param name       the tag name as specified in the TLD
     * @param tagfile    the path for the tagfile
     * @param tagLibInfo the TagLibraryInfo object associated with this TagInfo
     * @return a TagInfo object assembled from the directives in the tag file.
     */
    public static TagInfo parseTagFileDirectives(ParserController pc,
                                                 String name,
                                                 String path,
                                                 TagLibraryInfo tagLibInfo)
            throws JasperException {

        ErrorDispatcher err = pc.getCompiler().getErrorDispatcher();

        Node.Nodes page = null;
        try {
            page = pc.parseTagFileDirectives(path);
        } catch (FileNotFoundException e) {
            err.jspError("jsp.error.file.not.found", path);
        } catch (IOException e) {
            err.jspError("jsp.error.file.not.found", path);
        }

        TagFileDirectiveVisitor tagFileVisitor
                = new TagFileDirectiveVisitor(pc.getCompiler(), tagLibInfo, name,
                path);
        page.visit(tagFileVisitor);
        tagFileVisitor.postCheck();

        return tagFileVisitor.getTagInfo();
    }

    /**
     * Compiles and loads a tagfile.
     */
    private Class loadTagFile(Compiler compiler,
                              String tagFilePath, TagInfo tagInfo,
                              PageInfo parentPageInfo)
            throws JasperException {

        JspCompilationContext ctxt = compiler.getCompilationContext();
        JspRuntimeContext rctxt = ctxt.getRuntimeContext();
        JspServletWrapper wrapper =
                rctxt.getWrapper(tagFilePath);

        synchronized (rctxt) {
            if (wrapper == null) {
                wrapper = new JspServletWrapper(ctxt.getServletContext(),
                        ctxt.getOptions(),
                        tagFilePath,
                        tagInfo,
                        ctxt.getRuntimeContext(),
                        ctxt.getTagFileJarUrls().get(tagFilePath));
                rctxt.addWrapper(tagFilePath, wrapper);

                // Use same classloader and classpath for compiling tag files
                wrapper.getJspEngineContext().setClassLoader(
                        (URLClassLoader) ctxt.getClassLoader());
                wrapper.getJspEngineContext().setClassPath(ctxt.getClassPath());
            } else {
                // Make sure that JspCompilationContext gets the latest TagInfo
                // for the tag file.  TagInfo instance was created the last
                // time the tag file was scanned for directives, and the tag
                // file may have been modified since then.
                wrapper.getJspEngineContext().setTagInfo(tagInfo);
            }

            Class tagClazz;
            int tripCount = wrapper.incTripCount();
            try {
                if (tripCount > 0) {
                    // When tripCount is greater than zero, a circular
                    // dependency exists.  The circularily dependant tag
                    // file is compiled in prototype mode, to avoid infinite
                    // recursion.

                    JspServletWrapper tempWrapper
                            = new JspServletWrapper(ctxt.getServletContext(),
                            ctxt.getOptions(),
                            tagFilePath,
                            tagInfo,
                            ctxt.getRuntimeContext(),
                            ctxt.getTagFileJarUrls().get(tagFilePath));
                    tagClazz = tempWrapper.loadTagFilePrototype();
                    tempVector.add(
                            tempWrapper.getJspEngineContext().getCompiler());
                } else {
                    tagClazz = wrapper.loadTagFile();
                }
            } finally {
                wrapper.decTripCount();
            }

            // Add the dependants for this tag file to its parent's
            // dependant list.  The only reliable dependency information
            // can only be obtained from the tag instance.
            try {
                Object tagIns = tagClazz.newInstance();
                if (tagIns instanceof JspSourceDependent) {
                    Iterator iter =
                        /* GlassFish Issue 812
                        ((JspSourceDependent)tagIns).getDependants().iterator();
                        */
                            // START GlassFish Issue 812
                            ((java.util.List) ((JspSourceDependent) tagIns).getDependants()).iterator();
                    // END GlassFish Issue 812
                    while (iter.hasNext()) {
                        parentPageInfo.addDependant((String) iter.next());
                    }
                }
            } catch (Exception e) {
                // ignore errors
            }

            return tagClazz;
        }
    }

    /**
     * Implements a phase of the translation that compiles (if necessary)
     * the tag files used in a JSP files.  The directives in the tag files
     * are assumed to have been proccessed and encapsulated as TagFileInfo
     * in the CustomTag nodes.
     */
    public void loadTagFiles(Compiler compiler, Node.Nodes page)
            throws JasperException {

        tempVector = new Vector();
        page.visit(new TagFileLoaderVisitor(compiler));
    }

    /**
     * Removed the java and class files for the tag prototype
     * generated from the current compilation.
     *
     * @param classFileName If non-null, remove only the class file with
     *                      with this name.
     */
    public void removeProtoTypeFiles(String classFileName) {
        Iterator iter = tempVector.iterator();
        while (iter.hasNext()) {
            Compiler c = (Compiler) iter.next();
            if (classFileName == null) {
                c.removeGeneratedClassFiles();
            } else if (classFileName.equals(
                    c.getCompilationContext().getClassFileName())) {
                c.removeGeneratedClassFiles();
                tempVector.remove(c);
                return;
            }
        }
    }

    /**
     * A visitor the tag file
     */
    private static class TagFileDirectiveVisitor extends Node.Visitor {

        private static final JspUtil.ValidAttribute[] tagDirectiveAttrs = {
                new JspUtil.ValidAttribute("display-name"),
                new JspUtil.ValidAttribute("body-content"),
                new JspUtil.ValidAttribute("dynamic-attributes"),
                new JspUtil.ValidAttribute("small-icon"),
                new JspUtil.ValidAttribute("large-icon"),
                new JspUtil.ValidAttribute("description"),
                new JspUtil.ValidAttribute("example"),
                new JspUtil.ValidAttribute("pageEncoding"),
                new JspUtil.ValidAttribute("language"),
                new JspUtil.ValidAttribute("import"),
                new JspUtil.ValidAttribute("isELIgnored"),
                new JspUtil.ValidAttribute("deferredSyntaxAllowedAsLiteral"),
                new JspUtil.ValidAttribute("trimDirectiveWhitespaces")
        };

        private static final JspUtil.ValidAttribute[] attributeDirectiveAttrs = {
                new JspUtil.ValidAttribute("name", true),
                new JspUtil.ValidAttribute("required"),
                new JspUtil.ValidAttribute("fragment"),
                new JspUtil.ValidAttribute("rtexprvalue"),
                new JspUtil.ValidAttribute("type"),
                new JspUtil.ValidAttribute("description"),
                new JspUtil.ValidAttribute("deferredValue"),
                new JspUtil.ValidAttribute("deferredValueType"),
                new JspUtil.ValidAttribute("deferredMethod"),
                new JspUtil.ValidAttribute("deferredMethodSignature")
        };

        private static final JspUtil.ValidAttribute[] variableDirectiveAttrs = {
                new JspUtil.ValidAttribute("name-given"),
                new JspUtil.ValidAttribute("name-from-attribute"),
                new JspUtil.ValidAttribute("alias"),
                new JspUtil.ValidAttribute("variable-class"),
                new JspUtil.ValidAttribute("scope"),
                new JspUtil.ValidAttribute("declare"),
                new JspUtil.ValidAttribute("description")
        };

        private ErrorDispatcher err;
        private TagLibraryInfo tagLibInfo;

        private String name = null;
        private String path = null;
        private TagExtraInfo tei = null;
        private String bodycontent = null;
        private String description = null;
        private String displayName = null;
        private String smallIcon = null;
        private String largeIcon = null;
        private String dynamicAttrsMapName;
        private String example = null;

        private Vector attributeVector;
        private Vector variableVector;

        private HashMap<String, NameEntry> nameTable =
                new HashMap<String, NameEntry>();
        private HashMap<String, NameEntry> nameFromTable =
                new HashMap<String, NameEntry>();

        // The tag file's JSP version
        private Double jspVersionDouble;

        public TagFileDirectiveVisitor(Compiler compiler,
                                       TagLibraryInfo tagLibInfo,
                                       String name,
                                       String path) {
            err = compiler.getErrorDispatcher();
            this.tagLibInfo = tagLibInfo;
            this.name = name;
            this.path = path;
            attributeVector = new Vector();
            variableVector = new Vector();

            jspVersionDouble = Double.valueOf(tagLibInfo.getRequiredVersion());
        }

        public void visit(Node.JspRoot n) throws JasperException {
            /*
             * If a tag file in XML syntax contains a jsp:root element, the
             * value of its "version" attribute must match the tag file's JSP
             * version.
             */
            String jspRootVersion = n.getTextAttribute("version");
            if (jspRootVersion == null) {
                err.jspError(n, "jsp.error.mandatory.attribute", n.getQName(),
                        "version");
            }
            if (!jspRootVersion.equals(jspVersionDouble.toString())) {
                err.jspError(n, "jsp.error.tagfile.jspVersionMismatch",
                        jspRootVersion, jspVersionDouble.toString());
            }
            visitBody(n);
        }

        public void visit(Node.TagDirective n) throws JasperException {

            JspUtil.checkAttributes("Tag directive", n, tagDirectiveAttrs,
                    err);

            bodycontent = checkConflict(n, bodycontent, "body-content");
            if (bodycontent != null &&
                    !bodycontent.equals(TagInfo.BODY_CONTENT_EMPTY) &&
                    !bodycontent.equals(TagInfo.BODY_CONTENT_TAG_DEPENDENT) &&
                    !bodycontent.equals(TagInfo.BODY_CONTENT_SCRIPTLESS)) {
                err.jspError(n, "jsp.error.tagdirective.badbodycontent",
                        bodycontent);
            }
            dynamicAttrsMapName = checkConflict(n, dynamicAttrsMapName,
                    "dynamic-attributes");
            if (dynamicAttrsMapName != null) {
                checkUniqueName(dynamicAttrsMapName, Name.TAG_DYNAMIC, n);
            }
            smallIcon = checkConflict(n, smallIcon, "small-icon");
            largeIcon = checkConflict(n, largeIcon, "large-icon");
            description = checkConflict(n, description, "description");
            displayName = checkConflict(n, displayName, "display-name");
            example = checkConflict(n, example, "example");

            if (n.getAttributeValue("deferredSyntaxAllowedAsLiteral") != null
                    && Double.compare(jspVersionDouble,
                    Constants.JSP_VERSION_2_1) < 0) {
                err.jspError("jsp.error.invalidTagDirectiveAttrUnless21",
                        "deferredSyntaxAllowedAsLiteral");
            }

            // Additional tag directives are validated in Validator
        }

        private String checkConflict(Node n, String oldAttrValue, String attr)
                throws JasperException {

            String result = oldAttrValue;
            String attrValue = n.getAttributeValue(attr);
            if (attrValue != null) {
                if (oldAttrValue != null && !oldAttrValue.equals(attrValue)) {
                    err.jspError(n, "jsp.error.tag.conflict.attr", attr,
                            oldAttrValue, attrValue);
                }
                result = attrValue;
            }
            return result;
        }

        public void visit(Node.AttributeDirective n) throws JasperException {

            JspUtil.checkAttributes("Attribute directive", n,
                    attributeDirectiveAttrs, err);

            String attrName = n.getAttributeValue("name");
            boolean required = JspUtil.booleanValue(
                    n.getAttributeValue("required"));
            boolean rtexprvalue = true;
            String rtexprvalueString = n.getAttributeValue("rtexprvalue");
            if (rtexprvalueString != null) {
                rtexprvalue = JspUtil.booleanValue(rtexprvalueString);
            }
            boolean fragment = JspUtil.booleanValue(
                    n.getAttributeValue("fragment"));
            String type = n.getAttributeValue("type");

            String deferredValue = n.getAttributeValue("deferredValue");
            String deferredMethod = n.getAttributeValue("deferredMethod");
            String expectedType = n.getAttributeValue("deferredValueType");
            String methodSignature = n.getAttributeValue("deferredMethodSignature");
            if (Double.compare(jspVersionDouble,
                    Constants.JSP_VERSION_2_1) < 0) {
                if (deferredValue != null) {
                    err.jspError("jsp.error.invalidAttrDirectiveAttrUnless21",
                            "deferredValue");
                }
                if (deferredMethod != null) {
                    err.jspError("jsp.error.invalidAttrDirectiveAttrUnless21",
                            "deferredMethod");
                }
                if (expectedType != null) {
                    err.jspError("jsp.error.invalidAttrDirectiveAttrUnless21",
                            "deferredValueType");
                }
                if (methodSignature != null) {
                    err.jspError("jsp.error.invalidAttrDirectiveAttrUnless21",
                            "deferredMethodSignature");
                }
            }

            boolean isDeferredValue = JspUtil.booleanValue(deferredValue);
            boolean isDeferredMethod = JspUtil.booleanValue(deferredMethod);
            if (expectedType == null) {
                if (isDeferredValue) {
                    expectedType = "java.lang.Object";
                }
            } else {
                if (deferredValue != null && !isDeferredValue) {
                    err.jspError("jsp.error.deferredvaluewithtype");
                }
                isDeferredValue = true;
            }

            if (methodSignature == null) {
                if (isDeferredMethod) {
                    methodSignature = "void method()";
                }
            } else {
                if (deferredMethod != null && !isDeferredMethod) {
                    err.jspError("jsp.error.deferredmethodwithsignature");
                }
                isDeferredMethod = true;
            }

            if (fragment) {
                // type is fixed to "JspFragment" and a translation error
                // must occur if specified.
                if (type != null) {
                    err.jspError(n, "jsp.error.fragmentwithtype");
                }
                // rtexprvalue is fixed to "true" and a translation error
                // must occur if specified.
                rtexprvalue = true;
                if (rtexprvalueString != null) {
                    err.jspError(n, "jsp.error.frgmentwithrtexprvalue");
                }
            } else if (type == null) {
                if (isDeferredValue) {
                    type = "javax.el.ValueExpression";
                } else if (isDeferredMethod) {
                    type = "javax.el.MethodExpression";
                } else {
                    type = "java.lang.String";
                }
            } else if (isDeferredValue || isDeferredMethod) {
                err.jspError("jsp.error.deferredwithtype");
            }

            if (isDeferredValue || isDeferredMethod) {
                rtexprvalue = false;
            }
            TagAttributeInfo tagAttributeInfo =
                    new TagAttributeInfo(attrName,
                            required,
                            type,
                            rtexprvalue,
                            fragment,
                            description,
                            isDeferredValue,
                            isDeferredMethod,
                            expectedType,
                            methodSignature);
            attributeVector.addElement(tagAttributeInfo);
            checkUniqueName(attrName, Name.ATTR_NAME, n, tagAttributeInfo);
        }

        public void visit(Node.VariableDirective n) throws JasperException {

            JspUtil.checkAttributes("Variable directive", n,
                    variableDirectiveAttrs, err);

            String nameGiven = n.getAttributeValue("name-given");
            String nameFromAttribute = n.getAttributeValue("name-from-attribute");
            if (nameGiven == null && nameFromAttribute == null) {
                err.jspError("jsp.error.variable.either.name");
            }

            if (nameGiven != null && nameFromAttribute != null) {
                err.jspError("jsp.error.variable.both.name");
            }

            String alias = n.getAttributeValue("alias");
            if (nameFromAttribute != null && alias == null ||
                    nameFromAttribute == null && alias != null) {
                err.jspError("jsp.error.variable.alias");
            }

            String className = n.getAttributeValue("variable-class");
            if (className == null)
                className = "java.lang.String";

            String declareStr = n.getAttributeValue("declare");
            boolean declare = true;
            if (declareStr != null)
                declare = JspUtil.booleanValue(declareStr);

            int scope = VariableInfo.NESTED;
            String scopeStr = n.getAttributeValue("scope");
            if (scopeStr != null) {
                if ("NESTED".equals(scopeStr)) {
                    // Already the default
                } else if ("AT_BEGIN".equals(scopeStr)) {
                    scope = VariableInfo.AT_BEGIN;
                } else if ("AT_END".equals(scopeStr)) {
                    scope = VariableInfo.AT_END;
                }
            }

            if (nameFromAttribute != null) {
                /*
         * An alias has been specified. We use 'nameGiven' to hold the
		 * value of the alias, and 'nameFromAttribute' to hold the
		 * name of the attribute whose value (at invocation-time)
		 * denotes the name of the variable that is being aliased
		 */
                nameGiven = alias;
                checkUniqueName(nameFromAttribute, Name.VAR_NAME_FROM, n);
                checkUniqueName(alias, Name.VAR_ALIAS, n);
            } else {
                // name-given specified
                checkUniqueName(nameGiven, Name.VAR_NAME_GIVEN, n);
            }

            variableVector.addElement(new TagVariableInfo(
                    nameGiven,
                    nameFromAttribute,
                    className,
                    declare,
                    scope));
        }

        /*
         * Returns the vector of attributes corresponding to attribute
         * directives.
         */
        public Vector getAttributesVector() {
            return attributeVector;
        }

        /*
         * Returns the vector of variables corresponding to variable
         * directives.
         */
        public Vector getVariablesVector() {
            return variableVector;
        }

        /*
         * Returns the value of the dynamic-attributes tag directive
         * attribute.
         */
        public String getDynamicAttributesMapName() {
            return dynamicAttrsMapName;
        }

        public TagInfo getTagInfo() throws JasperException {

            if (name == null) {
                // XXX Get it from tag file name
            }

            if (bodycontent == null) {
                bodycontent = TagInfo.BODY_CONTENT_SCRIPTLESS;
            }

            String tagClassName = JspUtil.getTagHandlerClassName(path, err);

            TagVariableInfo[] tagVariableInfos
                    = new TagVariableInfo[variableVector.size()];
            variableVector.copyInto(tagVariableInfos);

            TagAttributeInfo[] tagAttributeInfo
                    = new TagAttributeInfo[attributeVector.size()];
            attributeVector.copyInto(tagAttributeInfo);

            return new JasperTagInfo(name,
                    tagClassName,
                    bodycontent,
                    description,
                    tagLibInfo,
                    tei,
                    tagAttributeInfo,
                    displayName,
                    smallIcon,
                    largeIcon,
                    tagVariableInfos,
                    dynamicAttrsMapName);
        }

        /**
         * Reports a translation error if names specified in attributes of
         * directives are not unique in this translation unit.
         * <p>
         * The value of the following attributes must be unique.
         * 1. 'name' attribute of an attribute directive
         * 2. 'name-given' attribute of a variable directive
         * 3. 'alias' attribute of variable directive
         * 4. 'dynamic-attributes' of a tag directive
         * except that 'dynamic-attributes' can (and must) have the same
         * value when it appears in multiple tag directives.
         * <p>
         * Also, 'name-from' attribute of a variable directive cannot have
         * the same value as that from another variable directive.
         */
        private void checkUniqueName(String name, Name type, Node n)
                throws JasperException {
            checkUniqueName(name, type, n, null);
        }

        private void checkUniqueName(String name, Name type, Node n,
                                     TagAttributeInfo attr)
                throws JasperException {

            HashMap<String, NameEntry> table =
                    (type == Name.VAR_NAME_FROM) ? nameFromTable : nameTable;
            NameEntry nameEntry = table.get(name);
            if (nameEntry != null) {
                if (type != Name.TAG_DYNAMIC
                        || nameEntry.getType() != Name.TAG_DYNAMIC) {
                    int line = nameEntry.getNode().getStart().getLineNumber();
                    err.jspError(n, "jsp.error.tagfile.nameNotUnique",
                            type.getAttribute(), type.getDirective(),
                            nameEntry.getType().getAttribute(),
                            nameEntry.getType().getDirective(),
                            Integer.toString(line));
                }
            } else {
                table.put(name, new NameEntry(type, n, attr));
            }
        }

        /**
         * Perform miscelleaneous checks after the nodes are visited.
         */
        void postCheck() throws JasperException {
            // Check that var.name-from-attributes has valid values.
            Iterator iter = nameFromTable.keySet().iterator();
            while (iter.hasNext()) {
                String nameFrom = (String) iter.next();
                NameEntry nameEntry = nameTable.get(nameFrom);
                NameEntry nameFromEntry = nameFromTable.get(nameFrom);
                Node nameFromNode = nameFromEntry.getNode();
                if (nameEntry == null) {
                    err.jspError(nameFromNode,
                            "jsp.error.tagfile.nameFrom.noAttribute",
                            nameFrom);
                } else {
                    Node node = nameEntry.getNode();
                    TagAttributeInfo tagAttr = nameEntry.getTagAttributeInfo();
                    if (!"java.lang.String".equals(tagAttr.getTypeName())
                            || !tagAttr.isRequired()
                            || tagAttr.canBeRequestTime()) {
                        err.jspError(nameFromNode,
                                "jsp.error.tagfile.nameFrom.badAttribute",
                                nameFrom,
                                Integer.toString(node.getStart().getLineNumber()));
                    }
                }
            }
        }

        private enum Name {
            ATTR_NAME("name", "attribute"),
            VAR_NAME_GIVEN("name-given", "variable"),
            VAR_NAME_FROM("name-from-attribute", "variable"),
            VAR_ALIAS("alias", "variable"),
            TAG_DYNAMIC("dynamic-attributes", "tag");

            private String attribute;
            private String directive;

            Name(String attribute, String directive) {
                this.attribute = attribute;
                this.directive = directive;
            }

            String getAttribute() {
                return this.attribute;
            }

            String getDirective() {
                return this.directive;
            }
        }

        static class NameEntry {
            private Name type;
            private Node node;
            private TagAttributeInfo attr;

            NameEntry(Name type, Node node, TagAttributeInfo attr) {
                this.type = type;
                this.node = node;
                this.attr = attr;
            }

            Name getType() {
                return type;
            }

            Node getNode() {
                return node;
            }

            TagAttributeInfo getTagAttributeInfo() {
                return attr;
            }
        }
    }

    /*
     * Visitor which scans the page and looks for tag handlers that are tag
     * files, compiling (if necessary) and loading them.
     */
    private class TagFileLoaderVisitor extends Node.Visitor {

        private Compiler compiler;
        private PageInfo pageInfo;

        TagFileLoaderVisitor(Compiler compiler) {

            this.compiler = compiler;
            this.pageInfo = compiler.getPageInfo();
        }

        public void visit(Node.CustomTag n) throws JasperException {
            TagFileInfo tagFileInfo = n.getTagFileInfo();
            if (tagFileInfo != null) {
                String tagFilePath = tagFileInfo.getPath();
                JspCompilationContext ctxt = compiler.getCompilationContext();
                if (ctxt.getTagFileJarUrls().get(tagFilePath) == null) {
                    // Omit tag file dependency info on jar files for now.
                    pageInfo.addDependant(tagFilePath);
                }
                Class c = loadTagFile(compiler, tagFilePath, n.getTagInfo(),
                        pageInfo);
                n.setTagHandlerClass(c);
            }
            visitBody(n);
        }
    }
}

